Reprinted from: 



Proceedings of Beach Preservation Technology '88 . 

 Florida Shore and Beach Preservation Association, 

 Tallahassee, FL, pp. 123-147, 1988. 



PREDICTION OF INITIAL PROFILE ADJUSTMENT 

 OF NOURISHED BEACHES TO WAVE ACTION 



Nicholas C. Kraus 1 and Magnus Larson 2 



ABSTRACT 



A newly developed numerical model of beach profile change is applied to 

 examine the adjustment of hypothetical beach fill designs exposed to 

 varying waves and water level. The model calculates net cross -shore sand 

 transport produced by breaking waves and simulates growth and movement of 

 the main longshore bar and the berm. Evolution of an "existing" beach 

 profile and two nourishment projects involving different fill templates is 

 simulated over a 30-day period which includes a 3 -day storm followed by a 

 7 -day recovery period. Relative advantages and disadvantages of the 

 templates are made evident, as well as the dependence of fill adjustment 

 on grain size. The results demonstrate the applicability of an emerging 

 technology for quantitative estimation of beach fill design. 



INTRODUCTION 



It has been empirically and theoretically established that the average 

 shape of the nearshore profile in equilibrium with the waves passing over it 

 is well approximated by the power law expression (Bruun 1954, Dean 1977) 



h = Ax 2/3 (1) 



in which h is the water depth, x is the distance from the mean position of 

 the shoreline (directed positive offshore), and A is a shape coefficient 

 that is mainly a function of sand size (Moore 1982) or fall speed (Dean 1987). 

 Equation 1 provides a simple means for estimating the ultimate (equilibrium) 

 shape of a beach fill of given grain size and may be considered one of several 

 "static" methods for calculating beach fill adjustment using an assumption for 

 the final form of the profile (e.g., Edelman 1968, 1972; Vallianos 1974; 

 Vellinga 1983). 



(1) Senior Research Scientist, Coastal Engineering Research Center, U.S. Army 

 Engr. Waterways Expt. Station, 3909 Halls Ferry Rd. , Vicksburg, MS 39180. 



(2) Assistant Professor, Department of Water Resources Engineering, Institute 

 of Science and Technology, University of Lund, Box 118, Lund S-221-00, 

 Sweden. 



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